The present invention relates to an apparatus, method and program for alarming abnormality in tire air-pressure.
It is difficult to detect decrease in tire air-pressure, in particular such as a run-flat tire which allows traveling even if air-pressure therein is zero. In the case a vehicle travels at high speed with a tire having decreased air-pressure, there has been a problem that the tire may blow out.
Various methods have been investigated to detect decrease in tire air-pressure. However, if tire air-pressure is completely zero, most of the methods cannot detect decrease in tire air-pressure since those methods conclude from acceleration variations that a road condition is bad and reject all data.
Japanese Unexamined Patent Publication No. 305011/1988 discloses a method for detecting decrease in tire air-pressure from wheel velocities of four-wheel tires on a vehicle by using a tire deflation warning system (DWS). However, this method can not detect that tire air-pressure is zero.
An object of the present invention is to provide an apparatus, method and program for detecting abnormality in tire air-pressure which allow detecting abnormality of a tire air-pressure even if a tire air-pressure is completely zero.